Big Bob is right Orb, a properly bedded rifle will put the first shot out of a clean cold barrel right in the group. If you have another scope though, I might try that too, parallax can cause odd shifts in zero, though not by very much. An inch or so at 100 is entirely possible and I personally wouldnt trust that simmons. If its the barrel heating up against some barrel channel contact, it should walk back to zero after four or five shots just like bigcountry said.